Membership Problem for the Modular Group

  • Yuri Gurevich ,
  • Paul Schupp

MSR-TR-2005-92 |

The modular group plays an important role in many branches of mathematics. We show that the membership problem for the modular group is polynomial time in the worst case. We also show that the membership problem for a free group remains polynomial time when elements are written in a normal form with exponents.